Concrete pavers layable in a herringbone pattern

ABSTRACT

First and second concrete pavers that are configured to form a paver system arrangeable in a herringbone pattern. A plurality of the first pavers and a plurality of the second pavers, which together form a kit of pavers, can be used to construct a permeable pavement with the herringbone pattern. The first and second pavers are preferably molded in a layer with the pavers arranged in the herringbone pattern. The layer can then be mechanically installed using suitable mechanical installation equipment.

FIELD OF THE INVENTION

The invention relates to concrete pavers. More particularly, theinvention relates to a concrete paver system that facilitates mechanicalinstallation of the pavers in a herringbone pattern.

BACKGROUND OF THE INVENTION

Concrete pavers are high strength modular concrete units that fittogether to create paved areas. Concrete pavers have been used for manyyears to construct paved areas for pedestrian and vehicular traffic.Concrete pavers have been used to pave walkways, driveways, streets,airport taxiways, parking lots, patios, and the like.

Many pavers are made with spacers on their sides to maintain a uniformspacing between the pavers. The spacers are designed to maintain aminimum joint width between the pavers that provides just enough spacefor sand to effectively fill the joints between the pavers. The sandbetween the pavers transfers shear loads between the pavers, therebyachieving vertical interlock of the pavers to prevent vertical movementof the pavers relative to one another. A common joint width for thesetypes of pavers is about 1.5 mm.

The water permeability of the pavement can be increased, when desirable,by increasing the joint width. The Interlocking Concrete PavementInstitute, Tech Spec Number 1, May 2001 Revision (the “ICPI Tech Spec”),suggests that permeable pavement have joint widths of about 10 mm toabout 30 mm. Accordingly, concrete pavers have been made with suitablespacer dimensions of this magnitude to create highly water permeablepavements.

In addition to water permeability, factors to be considered wheninstalling pavers are the anticipated loading on the pavers and theaesthetics sought by the customer. Concrete pavers can be laid in anumber of patterns to meet differing engineering requirements andaesthetic requirements. A popular pattern from both an aesthetic andengineering standpoint is a herringbone pattern. A herringbone patternis visually appealing, and is the most effective pattern for dispersingforces from braking and accelerating vehicles, thereby maintaininghorizontal interlock between the pavers. Herringbone patterns areusually installed with the lengths of the pavers at 45 degrees withrespect to the anticipated direction of pedestrian or vehicular traffic,or they are laid in a 90 degree pattern as shown in FIG. 1.

Pavers are increasingly being installed using mechanical installation.In mechanical installation, machinery is used to lift and place layersof pavers that are prearranged in their final laying pattern. Mechanicalinstallation increases the rate of paving, reduces worker fatigue, andreduces the risk of injury to workers.

SUMMARY OF THE INVENTION

The invention relates to a system of concrete pavers for use in creatinga pavement, including permeable pavement, that has a herringbone patternand that can be mechanically installed.

The system comprises first and second generally rectangular concretepavers that are configured to form a pavement, and that are configuredto be arranged in a herringbone pattern. A plurality of the first paversand a plurality of the second pavers, which together comprise a kit ofpavers, can be used to construct the pavement with the herringbonepattern.

The concrete pavers of the present invention are made in a dry castprocess that is well-known in the art. The mold used to make thesepavers is configured to make a plurality of both of the shapes ofpavers, arranged in the herringbone pattern. Each “drop” of pavers somade is then stacked on a shipping pallet as a successive layer. Amechanical laying machine can take an entire layer of pavers from theshipping pallet, and can install the entire layer of pavers at one time.

Each of the first and second pavers has a top surface, a bottom surface,a generally vertical first side surface, a generally vertical secondside surface opposite the first side surface, a generally vertical thirdside surface extending from the first side surface to the second sidesurface, and a generally vertical fourth side surface opposite the thirdside surface and extending from the first side surface to the secondside surface. The first and second side surfaces have generally equallengths and the third and fourth side surfaces have generally equallengths. The length of the first and second side surfaces is greaterthan the length of the third and fourth side surfaces. The first andsecond pavers have generally the same length, width and height.

The first paver has at least two spacers on the first side thereof andat least one spacer on the third side thereof, with the spacersextending outward from the first and third side surfaces of the firstpaver generally the same distance. The first paver is free of spacers onthe second and fourth side surfaces. In addition, a first of the spacerson the first side surface is positioned on one side of the midpoint ofthe length of the first side surface and a second of the spacers ispositioned from the midpoint to the end of the side surface furthestfrom the first spacer.

The second paver has at least two spacers on the first side surfacethereof and at least one spacer on the fourth side surface thereof, withthe spacers extending outward from the first and fourth side surfaces ofthe second paver generally the same distance as the spacers on the firstand third side surfaces of the first paver. The second paver is free ofspacers on the second and third side surfaces. Further, a first of thespacers of the second paver on the first side surface thereof ispositioned on one side of the midpoint of the length of the first sidesurface and a second of the spacers is positioned from the midpoint tothe end of the side surface furthest from the first spacer.

In one embodiment, the first and second pavers are configured so as tocreate a permeable pavement when installed, with the first and secondpavers having an overall width and length the same as that of anexisting non-permeable paver. With the first and second paversconfigured in this manner, the first and second pavers can be used on ajob site to produce a permeable pavement and the non-permeable paverscan be used on the same job site to produce a non-permeable pavement.Due to the similarity in size of the pavers, the permeable andnon-permeable pavements have generally similar appearances therebyproviding general visual continuity between the different types ofpavement. Further, due to their similarity in size, the first and secondpavers can be used to replace individual non-permeable pavers in anexisting non-permeable pavement. In this embodiment, the first andsecond pavers, together with the existing non-permeable pavers, form acomplete paving system that allows formation of permeable andnon-permeable pavement, each of which can be mechanically installed in aherringbone pattern, and with each pavement having a similar appearance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a section of pavement formed from first and secondpavers of the invention.

FIG. 2 is a perspective view of the first paver.

FIG. 3 is a top view of the first paver.

FIG. 4 is a cross-sectional view of a portion of the first paver takenalong line 4-4 of FIG. 3.

FIG. 5 is a perspective view of the second paver.

FIG. 6 is a top view of the second paver.

FIG. 7 is a top view of the mold showing the mold cavities used to formthe first and second pavers of the invention into a layer of pavers,including half size square filler pavers to complete a rectangular layerof pavers.

FIG. 8 is a perspective view of a rectangular layer of pavers producedby the mold of FIG. 7.

FIG. 9 is a top view of one of the half size square filler paversproduced by the mold of FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a system of concrete pavers for use in creating apavement having a herringbone pattern and that can be mechanicallyinstalled. The invention will be described with respect to theconstruction of a permeable pavement. However, the pavers can also beused to construct pavement that is not considered to be permeablepavement.

With reference initially to FIG. 1, the system comprises first andsecond concrete pavers 10A, 10B. A plurality of each of the pavers 10A,10B are laid in a herringbone pattern to form a pavement 12.

The pavers 10A, 10B are spaced apart from one another by spacers 14 thatare provided on the pavers to define joints 16 between the pavers. Thejoints are filled with a moisture permeable material, for example coarseaggregate or topsoil and grass. The joint width and the material fillingthe joints allow rainfall and other moisture to pass through thepavement 12, thereby increasing the drainage of rainfall and othermoisture through the pavement 12. The pavement 12 is constructed on topof a suitable bedding course and base course, for example No. 8aggregate and No. 57 aggregate, respectively.

The widths of the joints 16 are generally equal to each other.Preferably, the width of the joints 16 is less than or equal to about 15mm. These joint widths, together with the material that fills thejoints, provide a permeability that is similar to the permeability ofconventional permeable pavers. However, other joint widths could be useddepending upon how much water permeability is desired. FIG. 1illustrates the pavers 10A, 10B as being spaced apart from each otherwith no contact between them. This is to better illustrate the conceptsof the invention. It is to be realized that in actual use, the pavers10A, 10B would be in contact with one another through the spacers 14.

As shown in FIGS. 1, 3 and 6, each of the pavers 10A has a longitudinalaxis a-a and each of the pavers 10B has a longitudinal axis b-b. Theherringbone pattern in FIG. 1 is a 90 degree herringbone pattern wherethe longitudinal axes a-a are generally parallel to one another, thelongitudinal axes b-b are generally parallel to one another, and thelongitudinal axes a-a are generally perpendicular to the longitudinalaxes b-b. In addition, the pavers 10A are arranged along a plurality ofdiagonal axes d_(a) that are parallel to one another, and the pavers 10Bare arranged along a plurality of diagonal axes d_(b) that are parallelto one another and parallel to the axes d_(a).

Details of the pavers 10A, 10B will now be described with reference toFIGS. 2-6. Each paver 10A, 10B is generally rectangular and made fromdry cast concrete. The pavers are illustrated with generally rectilinearsides. However, the pavers could have one or more of the sides thatdeviate from rectilinear, for example opposite sides of the pavers couldbe serpentine, and still be considered generally rectangular.

Each paver 10A, 10B has a top surface 20 which during the intended useof the paver faces upward, a bottom surface 22 opposite the top surface20 (the bottom surface of the paver 10B is not visible in the figuresbut is generally similar to the bottom surface of the paver 10A), agenerally vertical first side surface 24 and a generally vertical secondside surface 26 opposite the first side surface, a generally verticalthird side surface 28 extending from the first side surface 24 to thesecond side surface 26, and a generally vertical fourth side surface 30opposite the third side surface and extending from the first sidesurface to the second side surface.

A chamfer 32 is provided between the top surface 20 and the sidesurfaces 24, 26, 28, 30. The intersection between the chamfer 32 and thetop surface 20 is preferably irregular, thereby making the top surface20 appear irregular, to enhance the appearance of the pavers 10A, 10B.

For each paver 10A, 10B, the first and second side surfaces 24, 26 eachhave a length L₁ generally equal to each other, and the third and fourthside surfaces 28, each have a length L₂ generally equal to each other.As shown in FIGS. 3 and 6, L₁ is greater than L₂. Preferably, L₁ istwice L₂. Further, the pavers 10A, 10B have generally equal length (L₁),width (L₂), and height (H) dimensions.

Turning now to FIGS. 2-4, the paver 10A is integrally formed with atleast two of the spacers 14 on the first side surface 24 and at leastone of the spacers 14 on the third side surface 28. The spacers 14extend outwardly from the respective side surface approximately the samedistance D. The paver 10A is free of spacers on the second side surface26 and on the fourth side surface 30, and those side surfaces 26, 30 arepreferably generally planar. However, the side surfaces 26, 30, as wellas the side surfaces 24, 28, could be provided with projections thatextend outwardly therefrom a distance less than the distance D. In thatcase, those projections would not abut against adjacent pavers and wouldnot function as spacers when the pavers are arranged in a herringbonepattern as described herein.

As best seen in FIG. 4, each spacer 14 extends nearly the entire heightH of the paver 10A, from the bottom surface 22 to adjacent the topsurface 20. The upper end of each spacer 14 near the top surface 20 hasa chamfer 34 so that the top of the spacer 14 is disposed at an angle αto horizontal. This configuration helps to hide the spacers 14 when thepavers are laid and permeable material fills the joints 16.

Further, as best seen in FIG. 3, the spacers 14 are tapered whereby thespacers decrease in width W from the respective side surfaces 24, 28 totheir free ends. Moreover, the spacers 14 on the side surface 24 aredisposed on opposite sides of the midpoint mp of the length of the sidesurface 24, while the spacer 14 on the side surface 28 is disposed onone side of the longitudinal axis a-a. One spacer on the first sidesurface 24 is spaced a distance L₃ from the fourth side surface 30, andthe spacers 14 on the first side surface 24 are spaced a distance L₄from each other. The spacer 14 on the side surface 28 is spaced adistance L₅ from the first side surface 24.

The paver 10B is generally similar to the paver 10A, but instead ofhaving a spacer 14 on the third side surface 28, the paver 10B includesat least one spacer 14 on the fourth side surface 30, and the third sidesurface is free of spacers, as illustrated in FIGS. 5 and 6. Further,the positioning of the spacers 14 on the first side surface 24 of paver10B is different than in paver 10A so that distance L₃ is now measuredfrom the third side surface 28.

Exemplary dimensions for the pavers 10A, 10B are as follows:

Paver 10A Paver 10B L₁ 264 mm 264 mm L₂ 124 mm 124 mm H  80 mm  80 mm L₃ 30 mm  30 mm L₄ 160 mm 160 mm L₅  30 mm  30 mm D  15 mm  15 mm W  25 mm 25 mm α  30 degrees  30 degrees

These exemplary dimensions provide the pavers 10A, 10B with a face size(measured between the side surfaces 24, 26 and 28, 30) and overallwidths and lengths (measured from the tip of spacer 14 on side surface24 to the opposite side surface 26 and from the tip of spacer 14 on sidesurface 28 to the opposite side surface 30) that are the same as anexisting non-permeable paver, the Holland paver by Anchor Block Companyof Minnetonka, Minn. Pavers 10A, 10B having these exemplary dimensionscan be used together with Holland pavers on a job site to producepermeable pavement (using the pavers 10A, 10B) and non-permeablepavement (using Holland pavers) as needed, with the permeable andnon-permeable pavements having generally similar appearances therebyproviding general visual continuity between the different types ofpavement. Further, due to their similarity in size, individual pavers10A, 10B having these exemplary dimensions can be used to replaceindividual Holland pavers in an existing pavement. This concept ofmaking the overall widths and lengths of the pavers 10A, 10B the same asan existing non-permeable paver can be used with pavers other thanHolland pavers.

With reference to FIG. 7, a mold 50 having a plurality of first andsecond mold cavities 52A, 52B suitable for forming the pavers 10A, 10B,respectively, is illustrated. The cavities 52A, 52B are arranged in aherringbone pattern so that the resulting pavers are molded in aherringbone pattern.

Each mold cavity 52A, 52B is generally rectangular, with first 54,second 56, third 58 and fourth 60 side faces, an open top and an openbottom. The side faces 54, 56, 58, 60 are generally vertical and havedimensions suitable for forming the side surfaces of the pavers 10A,10B.

Each of the first cavities 52A has spacer cavities 62 formed in the sideface 54 and in the side face 58 for forming the spacers 14 on the paver10A. Similarly, each of the second cavities 52B has spacer cavities 62formed in the side face 54 and in the side face 60 for forming thespacers 14 on the paver 10B. In the preferred embodiment, the side faces56, 60 of the first cavities 52A and the side faces 56, 58 of the secondcavities 52B are free of spacer cavities to form corresponding paverside surfaces that are planar and free of spacers.

The mold 50 is also provided with generally square mold cavities 64around the perimeter thereof to complete a generally rectangular paverlayer mold. The mold cavities 64 fill in gaps between the cavities 52A,52B that are present as a result of the herringbone arrangement of thecavities 52A, 52B. The cavities 64 are configured to produce a generallysquare paver 70, illustrated in FIG. 9, that is approximately half thesize of the pavers 10A, 10B. Each cavity 64 is similar in constructionto the cavities 52A, 52B, except for the square shape and the presenceof only two spacer cavities 66, each of which is located approximatelyhalfway along two adjacent sides of the cavity 64. The result is thepaver 70 shown in FIG. 9, with spacers 14 halfway along adjacent sides72, 74 of the paver 70.

To produce the pavers 10A, 10B, 70 the open bottoms of the mold cavities52A, 52B, 64 are temporarily closed. In certain molding machines,closure can be achieved using a flat pallet that is brought intoposition underneath the mold 50. Once the bottoms are closed, dry castconcrete is introduced into the mold cavities through the open tops ofthe mold cavities. The concrete in each mold cavity is then consolidatedthrough vibratory action and compaction that are well-known in the art.Such consolidation produces pre-cured concrete pavers. The bottoms ofthe mold cavities are then reopened, and the pre-cured concrete paversare then discharged from the mold cavities through the reopened bottomsof the molds. Discharge can occur by lowering the pallet relative to themold, with the stripper shoes pushing the pre-cured pavers out throughthe bottom. The pavers are then cured using known curing techniques.

The result is a rectangular layer 80 of pavers 10A, 10B, 70, illustratedin FIG. 8, where the pavers 10A, 10B are molded in a herringbone patternand the half pavers 70 fill in the sides of the rectangular paver layer.When a pavement is produced using a plurality of the layers 80, thelayers 80 are preferably laid so that the pavers 70 in one layer arenext to pavers 70 in an adjacent layer 80. The pavers 70 can then beremoved by hand and replaced with one of the pavers 10A, 10B.

The entire layer 80 can be mechanically installed. The equipment used toinstall the layer 80 can be motorized or non-motorized. Further detailson mechanical installation of concrete pavers and the function of suchmachinery are described in Interlocking Concrete Pavement Institute'sTech Spec Number 11, 2000 Revision.

-   -   (A) each first paver having no chamfer between the bottom        surface and the third side surface at least at the at least one        spacer on the third side surface; and    -   (B) each first paver having a chamfer between the top surface        and the third side surface at least at the at least one spacer        on the third side surface;        -   (iii) the spacers on each first paver extending outward from            the first and third surfaces generally the same distance;        -   (iv) the first paver being free of spacers on the second and            fourth side surfaces; and        -   (v) each first paver being configured so that when            positioned with the bottom surface directed down, the first            side surface is a next side clockwise around the first paver            from the third side surface;    -   (c) a plurality of second generally rectangular pavers; the        second pavers each having: a top surface and an opposite bottom        surface; a generally vertical first side surface; a generally        vertical second side surface opposite the first side surface; a        generally vertical third side surface extending from the first        side surface to the second side surface; and a generally        vertical fourth side surface opposite the third side surface and        extending from the first side surface to the second side        surface;        -   (i) the first and second side surfaces having generally            equal lengths;        -   (ii) the third and fourth side surfaces having generally            equal lengths;        -   (iii) the lengths of the first and second side surfaces            being greater than the lengths of the third and fourth side            surfaces; and    -   (d) each second paver further having:        -   (i) at least first and second spacers on the first side            thereof;            -   (A) each second paver having no chamfer between the                bottom surface and the first side surface at least at                the at least first and second spacers on the first side                surface;            -   (B) the first pavers each having a chamfer between the                top surface and the first side surface at least at the                at least first and second spacers on the first side                surface; and

1-28. (canceled)
 29. A kit of concrete pavers for making a herringbone paver system; the kit comprising: (a) a plurality of first, generally rectangular pavers; the first pavers each having: a top surface and an opposite bottom surface; a generally vertical first side surface; a generally vertical second side surface opposite the first side surface; a generally vertical third side surface extending from the first side surface to the second side surface; and, a generally vertical fourth side surface opposite the third side surface and extending from the first side surface to the second side surface; (i) the first and second side surfaces having generally equal lengths; (ii) the third and fourth side surfaces having generally equal lengths; (iii) the lengths of the first and second side surfaces being greater than the lengths of the third and fourth side surfaces; and, (b) each first paver further having: (i) at least first and second spacers on the first side surface thereof; (A) each first paver having no chamfer between the bottom surface and the first side surface at least at the at least first and second spacers on the first side surface; (B) each first paver having a chamfer between the top surface and the first side surface at least at the at least first and second spacers on the first side surface; and, (C) for each first paver, a first of the spacers on the first side surface being positioned on one side of a midpoint of the length of the first side surface; and a second of the spacers being positioned at a location between the midpoint and the end of the first side surface farthest from the first of the spacers on the first side surface; (ii) at least one spacer on the third side surface; (C) a first of the spacers on the first side surface being positioned on one side of a midpoint of the length of the first side surface; and a second of the spacers being positioned at a location between the midpoint and an the end of the first side surface farthest from the first of the spacers on the first side surface; (ii) at least one spacer on the fourth side surface; (A) each second paver having no chamfer between the bottom surface and the fourth side surface at least at the at least one spacer on the fourth side surface; and (B) each second paver having a chamfer between the top surface and the fourth side surface at least at the at least one spacer on the fourth side surface; (iii) the spacers on each second paver extending outward from the first and fourth surfaces generally the same distance; (iv) the second pavers each being free of spacers on the second and third side surfaces; and (v) each second paver being configured so that when positioned with the bottom surface directed down, the first side surface is a next side located counterclockwise around the second paver from the fourth side surface; and, (e) the first and second pavers each having generally the same length, width, and height.
 30. A kit of concrete pavers according to claim 29 wherein: (a) the third side surface of each first paver has one spacer thereon.
 31. A kit of concrete pavers according to claim 30 wherein: (b) the fourth side surface of each second paver has one spacer thereon.
 32. A kit of concrete pavers according to claim 29 wherein: (a) the first side surface of each first paver has two spacers thereon; and, (b) the first side surface of each second paver has two spacers thereon.
 33. A kit of concrete pavers according to claim 29 wherein: (a) each spacer of each first paver and each spacer of each second paver extends from a side surface a distance of less than or equal to 15 mm.
 34. A kit of concrete pavers according to claim 29 wherein: (a) the second side of each first paver has a length that is twice a length of each fourth side of each first paver; and (b) the second side of each second paver has a length that is twice a length of each third side of each second paver.
 35. A kit of concrete pavers according to claim 29 including: (a) a plurality of third, generally square, pavers; the third pavers each having: a top surface and a bottom surface; a generally vertical first side surface; a generally vertical second side surface opposite the first side surface; a generally vertical third side surface extending from the first side surface to the second side surface; and, a generally vertical fourth side surface opposite third side surface and extending from the first side surface to the second side surface; (i) the first, second, third and fourth side surfaces having generally equal lengths; (ii) each third paver further having: (A) at least one spacer on the first side surface thereof; and, (B) at least one spacer on the third side surface thereof.
 36. A kit of concrete pavers according to claim 35 wherein: (a) the lengths of the first, second, third and fourth sides of the third pavers is half a length of each second side of each first paver and each second side of each second paver.
 37. A kit of concrete pavers according to claim 29 wherein: (a) each paver is a dry cast concrete paver.
 38. A layer of concrete pavers suitable for mechanical installation; the layer comprising: (a) a plurality of first, pavers; the first pavers each having: a top surface and an opposite bottom surface; a first side surface; a second side surface opposite the first side surface; a third side surface extending from the first side surface to the second side surface; and a fourth side surface opposite the third side surface; (i) each first paver further having: (A) at least first and second spacers on the first side surface thereof; (1) each first paver having no chamfer between the bottom surface and the first side surface at least at the at least first and second spacers on the first side surface; (2) each first paver having a chamfer between the top surface and the first side surface at least at the at least first and second spacers on the first side surface; and, (B) at least one spacer on the third side surface; (1) each first paver having no chamfer between the bottom surface and the third side surface at least at the at least one spacer on the third side surface; and (2) each first paver having a chamfer between the top surface and the third side surface at least at the at least one spacer on the third side surface; (C) each spacer on each first paver extending outward from the first and third surfaces generally the same distance; (D) the first paver being free of spacers on the second and fourth side surfaces; and (E) each first paver being configured so that when positioned with the bottom surface directed down, the first side surface is a next side clockwise around the first paver from the third side surface; (b) a plurality of second pavers; the second pavers each having: a top surface and an opposite bottom surface; a first side surface; a second side surface opposite the first side surface; a third side surface extending from the first side surface to the second side surface; and a fourth side surface opposite the third side surface; (i) each second paver further having: (A) at least first and second spacers on the first side thereof; (1) each second paver having no chamfer between the bottom surface and the first side surface at least at the at least first and second spacers on the first side surface; (2) the first pavers each having a chamfer between the top surface and the first side surface at least at the at least first and second spacers on the first side surface; and (B) at least one spacer on the fourth side surface; (1) each second paver having no chamfer between the bottom surface and the fourth side surface at least at the at least one spacer on the fourth side surface; and (2) each second paver having a chamfer between the top surface and the fourth side surface at least at the at least one spacer on the fourth side surface; (C) the spacers on each second paver extending outward from the first and fourth surfaces generally the same distance; (D) the second pavers each being free of spacers on the second and third side surfaces; and (E) each second paver being configured so that when positioned with the bottom surface directed down, the first side surface is a next side located counterclockwise around the second paver from the fourth side surface; (c) the first and second pavers each having generally the same length, width, and height; and (d) the first and second pavers being positioned in a pattern: (i) with the bottom surfaces of each of the first and second pavers directed down; (ii) with all first pavers oriented with the third side of each directed in a first direction; (iii) with all second pavers oriented with a fourth side of each directed in a second direction; the second direction being generally perpendicular to the first direction; and (iv) with each two adjacent ones of the first and second pavers within the herringbone pattern having at least one spacer therebetween.
 39. A layer of pavers according to claim 38 wherein: (a) the third side surface of each first paver has one spacer thereon; and (b) the fourth side surface of each second paver has one spacer thereon.
 40. A layer of pavers according to claim 39 wherein: (a) the first side surface of each first paver has two spacers thereon; and (b) the first side surface of each second paver has two spacers thereon.
 41. A layer of pavers according to claim 39 wherein: (a) each spacer of each first paver and each spacer of each second paver extends from a side surface a distance of less than or equal to 15 mm.
 42. A layer of pavers according to claim 41 wherein: (a) the second side of each first paver has a length that is twice a length of each fourth side of each first paver; and (b) the second side of each second paver has a length that is twice a length of each third side of each second paver.
 43. A layer of pavers according to claim 42 wherein: (a) the layer includes a plurality of generally square pavers each positioned in selected edge spaces between selected first and second pavers, to fill in sides of the layer of pavers. 